shell: alarm: add command to enable/disable the alarm

include/shell/alarm.h

@@ -0,0 +1,3 @@
+#pragma once
+
+int shell_alarm(struct console *con, size_t argc, const char **argv);

source/shell/Makefile

@@ -1,3 +1,4 @@
+obj-y += source/shell/alarm.o
 obj-y += source/shell/args.o
 obj-y += source/shell/boot.o
 obj-y += source/shell/buzzer.o

source/shell/alarm.c

@@ -0,0 +1,28 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <libopencm3/stm32/gpio.h>
+
+#include <console.h>
+#include <rtc.h>
+
+int shell_alarm(struct console *con, size_t argc, const char **argv)
+{
+	int state = 0;
+	uint32_t timeout = 10;
+
+	if (argc >= 2)
+		timeout = strtoul(argv[0], NULL, 0);
+
+	if (argc >= 1)
+		state = (strcmp(argv[1], "on") == 0);
+
+	if (state) {
+		alarm_enable(timeout);
+	} else {
+		alarm_disable();
+	}
+
+	return 0;
+}